Dietary fat has been receiving bad press for years. At first it was just saturated fats, because they can raise blood cholesterol. Conversely, polyunsaturated and monounsaturated fats were thought to be good because they did not do so.
Then all fat was deemed "bad", and Americans were urged to consume as little as they could. Some have even gone so far as to advocate giving young children (under 2 years of age) non-fat milk. This is advice that no responsible pediatrician would endorse.
A major rationale for this fat obsession has been the realization that obesity is increasing in the United States. Since fat is the most energy-dense nutrient (9 calories per gram), it made sense to warn people that a diet high in fat could lead to overconsumption of calories, and that to lose weight one should cut down on fat. There was also a tendency to equate dietary fat with fat on one's body, and thus to condemn all dietary fat.
And yet, even though Americans did slightly decrease the percent of their calories from fat, obesity continued to increase. The problem was that in all the hullabaloo about fat, Americans lost sight of the fact that what counts the most in weight loss is calories, not their source. And even though we did decrease fat percent, total calories went up.
It is with some relief, therefore, that we learn the latest version of the U.S. Department of Agriculture's Dietary Guidelines steps away from language that implies that dietary fat is 'bad'.
Rather than instruct Americans to aim for a 'low-fat' diet, the latest version of the Guidelines proposes to change that to a 'diet that is moderate in fat.' In both versions, the recommendation is for thirty percent of calories from fat, but in the newer one the advice is aimed at avoiding extremes. Further, the newer version recognizes that some dietary fat is essential, and that a diet that is low in fat is not necessarily low in calories.
Dietary fat contributes to human nutrition and well-being in many ways. In addition to its basic function as a source of energy, fat is a carrier of vitamins A, D, E and K; it also contains essential fatty acids, as well as flavor and aroma substances. Although eating saturated fats is still stigmatized for increasing blood cholesterol, some also contain specific disease-inhibiting components. Current research findings suggest that at least some of these fats are less villainous than previously thought. For example, milk fat contains anti-cancer substances such as conjugated linoleic acid (CLA). Further, one saturated fat found in dairy and meat products, stearic acid does not seem to raise blood cholesterol levels.
When it comes to obesity, we must remember that obesity can arise from eating too much of anything, as excess calories from any source can be converted to body fat. Many current American lifestyles involve simply eating too many calories. When coupled with a lack of exercise, such lifestyles are obviously a dangerous invitation to fatness.
A very important characteristic of fats is their ability to enhance the palatability of foods. Flavor and aroma molecules are fat-soluble. Not only does fat serve as their carrier, it safeguards them against loss by evaporation, oxidation or reaction with other food components. That's why fat-containing foods are more tasty than their low- or no-fat counterparts.
The sensation of richness in the mouth is imparted to foods by fat. The effect of adding milk to breakfast cereal is a good example. Skim milk does very little to enhance the palatability of this food, but milk with only 1 or 2% fat produces a noticeable improvement. This is due to the remarkable effect that tiny fat particles have on the sensation of richness. Homogenizing the fat, such as in homogenized milk or half-and-half, greatly enhances the richness sought in ingredients for sauces, toppings and soups. Thus, foods do not need to be swimming in fat to taste good, but their flavor can greatly benefit from some fat in the right form.
We shouldn't have to punish ourselves by eating bland-tasting foods in order to protect our health and waistlines. The dissatisfaction resulting from a too-restricted diet can leave one still vaguely hungry for something else. Eating should be a joy. Having a sensible amount of fat in a sensible amount of food is a good way to add both valuable nutrients, as well as flavor and pleasure to the diet.